no sex drive ever

Okay so I just turned 18 but i lost my virginity at 15 , I've been with my boyfriend for about 6 months and we see each other very often he's so sweet and handsome he's so amazing and he's always trying to have sex and do stuff but when he touches me I just feel uncomfortable like I can't relax and I hate having to do foreplay . my boyfriend is 19 btw. idk why but I've had zero sex drive for like the past 2 months. do you think it could be my nexplanon bc?